DRAWING DATA GENERATION METHOD, PROCESSING APPARATUS, STORAGE MEDIUM, DRAWING APPARATUS, AND ARTICLE MANUFACTURING METHOD
A generation method of generating drawing data for performing drawing on a substrate by a drawing apparatus based on pattern data associated with a two-dimensional grid include: dividing the two-dimensional grid into a plurality of rectangular regions based on an angle by which the pattern data is rotated; and obtaining a translation amount of partial data of the pattern data with respect to each of the plurality of rectangular regions based on the angle.
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1. Field of the Invention
The present invention relates to a drawing data generation method, processing apparatus, storage medium, drawing apparatus, and article manufacturing method.
2. Description of the Related Art
Recently, a charged particle beam drawing apparatus has been used as an apparatus which draws the pattern of a semiconductor integrated circuit. When drawing a pattern by using the charged particle beam drawing apparatus, design pattern data created by CAD or the like needs to be converted into a data format which can be input to the charged particle beam drawing apparatus. In general, design pattern data generated by CAD or the like is vector format data (vector data) formed from end point data of a figure or the like, and drawing data input to the apparatus is binary or multilevel bitmap format data (raster data). A series of intermediate processing data until drawing data is generated from design pattern data will be called “pattern data”.
Errors originated from a drawing apparatus and drawing step include a mechanical position error, optical aberration, and an overlay error with respect to an underlayer. To correct these errors and draw a desired pattern, design pattern data and drawing data need to undergo geometrical conversion. This geometrical conversion is also called correction processing. Examples of the geometrical conversion are magnification, translation, and rotation operations, and sometimes include higher-order operations or non-linear operations. These correction processes are performed in the course of data conversion. Which of vector data and raster data is used as data to be processed has a tradeoff with respect to necessary performance. Although correction processing can be performed for vector data in terms of calculation accuracy, raster data is more advantageous in terms of the complexity of the processing circuit. Note that the installation cost and data amount depend on a target pattern and the contents of correction processing, and this determination cannot be made unconditionally.
In a drawing method disclosed in Japanese Patent Laid-Open No. 2003-297732, a position shift between a shape to be drawn with a charged particle beam and the shape of a target pattern is approximated by a high-order polynomial, and data is translated based on the approximation result. As for the connecting portion of the pattern, a margin is set at the boundary of data to suppress a connection shift. In a drawing method disclosed in Japanese Patent Laid-Open No. 2006-086182, the center positions of a shape to be drawn with a charged particle beam and the shape of a desired pattern are aligned by translating drawing data in alignment between these shapes, and a rotation shift is canceled by a biaxial deflector. Even in this case, as for the connecting portion of the pattern, a margin is set at the boundary of data to suppress a connection shift.
As the integration degrees and scales of semiconductor integrated circuits increase, the data amount of design pattern data is increasing and correction processing is becoming more accurate (that is, the correction amount is greatly decreasing). The method in Japanese Patent Laid-Open No. 2003-297732 implements high-accuracy correction processing, but needs to use approximation by a high-order polynomial for calculation of a correction amount. Thus, correction processing in Japanese Patent Laid-Open No. 2003-297732 requires an approximation calculation circuit for a trigonometric function or a large-scale lookup table. An operation circuit for the correction processing becomes expensive. In addition, the correction processing in Japanese Patent Laid-Open No. 2003-297732 is only correction processing by translation and cannot correct a rotation error. The drawing method in Japanese Patent Laid-Open No. 2006-086182 can correct a rotation error. However, calculation of a correction amount requires an expensive operation circuit, and a biaxial deflector is required separately to cancel a rotation shift.
In the related art, an expensive operation circuit is necessary, and another mechanism sometimes needs to be arranged in addition to data. Further, along with an increase in data amount to be processed, operation circuits for data conversion and correction processing become sophisticated and upsized. As a result, the throughput drops and the apparatus cost rises. In other words, the processing efficiency of correction processing needs to be improved without separately adding a mechanism.
Next, it is confirmed whether a rotation operation requiring an expensive operation circuit can be reduced in order to improve the processing efficiency.
In
The present invention provides, for example, a technique advantageous in efficiency with which generation of drawing data, accompanied by processing concerning rotation of pattern data, is executed.
The present invention in its one aspect provides a generation method of generating drawing data for performing drawing on a substrate by a drawing apparatus based on pattern data associated with a two-dimensional grid, the method comprising steps of: dividing the two-dimensional grid into a plurality of rectangular regions based on an angle by which the pattern data is rotated; and obtaining a translation amount of partial data of the pattern data with respect to each of the plurality of rectangular regions based on the angle.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Details of a generation method of generating drawing data for performing drawing on a substrate by a drawing apparatus based on pattern data represented by dots on two-dimensional grids according to the present invention will be described with reference to illustrated embodiments. In the present invention, when drawing is performed using the drawing apparatus in accordance with pattern data, rotation, shift (translation), and a change of the magnification of a pattern occur.
First EmbodimentPattern data correction processing in a drawing data generation method according to the first embodiment will be described with reference to
Rotation operation replacement processing shown in
x′=x cos(TH)−y sin(TH)
y′=x sin(TH)+y cos(TH) (1)
When a LUT is used for calculation of a trigonometric function, a LUT which summarizes the correspondence between the rotation angle TH and the sin and cos values is prepared separately. The calculation of equations (1) is performed by sequentially searching the LUT for the cos(TH) and sin(TH) values and replacing them with the detected values by the processing apparatus 1. The conventional processing apparatus 1 obtains a pattern surrounded by a solid line in
To the contrary, the processing apparatus 1 according to the first embodiment of the present invention calculates a division length L first in step S1 prior to correction processing. The division length L is an interval (grid size) between adjacent straight lines among two straight line groups which are parallel to the X- and Y-axes, respectively, and divide two-dimensional grids into rectangular regions of the same size. The division length L is determined so that an amount obtained by multiplying the division length L and the rotation angle TH becomes, for example, one grid size. The amount obtained by multiplying the division length L and the rotation angle TH may be an integer multiple of the grid size, or may be the LSB (Least Significant Bit) as long as the data accuracy can be maintained in the course of processing. As the division length L, the grid unit, an integer multiple of it, or a value rounded at the LSB is used for discretization. For example, when the result of equations (2) is “7.1”, the value rounded at the LSB is “7” obtained by rounding the decimal part.
In the first embodiment, the division length L is a size corresponding to an integer multiple of grids, as shown in
The rotation angle TH is not limited to these values, and the design allowance of the apparatus may be substituted. Note that the first embodiment will describe that the rotation angle TH takes one value. After the end of calculating the division length L, the processing apparatus 1 divides each pattern (partial pattern) included in the pattern data by the determined division length L, and acquires partial data of each rectangular region based on the division length L. In step S2, the processing apparatus 1 sets the number N of patterns (figures) included in the pattern data in an unprocessed figure counter n. In step S3, a loop of figure division processing (first processing) starts. This loop is circulated until n=0, that is, all figures are processed. Since there is one figure in the schematic views of
In the loop, the processing apparatus 1 first reads one figure from the pattern data (step S4). At this time, attention is paid to a grid in which the feature point P1 of the read figure exists. In step S5, the processing apparatus 1 determines whether the read figure falls within a rectangular region defined by the division length in the division determination of the next step. In
If the processing apparatus 1 determines in the division determination of step S5 that the figure lies across two or more rectangular regions, it determines that division processing is necessary for the figure, and performs the following processing. In step S6, the processing apparatus 1 increments the unprocessed figure counter n by one, and notifies that the number of figures to be processed increases as a result of the division processing. Then, in step S7, the processing apparatus 1 obtains intersection points (division coordinate position Q) between the figure and rectangular regions generated when the figure is divided into rectangular regions by the division length L. At this time, it suffices to obtain division coordinate position for only a rectangular region of interest. For a figure lying across two or more rectangular regions, division coordinate positions are sequentially calculated after dividing the figure. After obtaining the division coordinate positions, the processing apparatus 1 saves a figure Q1-P2-P3-Q2 outside the rectangular region of interest as a new figure in the pattern data in step S8. Subsequently, in step S9, the processing apparatus 1 updates the figure in the rectangular region of interest to be a figure P1-Q1-Q2-P4 fitting in the rectangular region by using the division coordinate positions. The division processing then ends.
In step S10, as for a figure to be processed, the processing apparatus 1 calculates the typical coordinate position D of the figure for which a shift amount along each coordinate axis is determined to correct a rotation angle (second processing). The typical coordinate position of partial data is obtained by normalizing original coordinate values by the division length L. The typical coordinate position of the figure P1-Q1-Q2-P4 is (0, 0), and that of the figure Q1-P2-P3-Q2 is (1, 0). More specifically, the typical coordinate position of each figure is determined using the coordinate values of a feature point nearest the origin or rotation center, or the barycentric coordinate values of a feature point. In step S11, the processing apparatus 1 calculates the typical coordinate position of the figure, adds the information to the figure of the partial data, and saves it. That is, figure data to be stored in the pattern data has information of the figure and coordinate information of the feature point. After the end of processing all figures, the loop ends (step S12), and the rotation operation replacement processing ends. The resultant output is rotation component-replaced pattern data obtained by adding coordinate information to original pattern data.
Referring back to
x′=Mx×x
y′=My×y (2)
Similarly, as for the shift correction operation, letting S(Sx, Sy) be the shift amount, the coordinates x′ and y′ of the vertex after the shift correction operation are calculated according to equations (3) using the shift amounts Sx and Sy:
x′=x+Sx
y′=y+Sy (3)
In the first embodiment in which pattern data has coordinate information, the rotation of a pattern is replaced with a shift in the following way. By using the typical coordinate position D(Dx, Dy) of the partial pattern, the rotation angle TH, and the division length L, the processing apparatus 1 obtains shift amounts SR(SRx, SRy) for correcting a rotation amount, according to equations (4):
SRx=−L×TH×Dy
SRy=L×TH×Dx (4)
The obtained shift amounts SR for correcting a rotation amount can be processed at the same time as an existing shift. Thus, the processing apparatus 1 according to the first embodiment uses equations (5) instead of equations (3) for the shift operation:
x′=x+Sx+SRx
y′=y+Sy+SRy (5)
When only rotational correction is applied without magnification correction or shift, a pattern indicated by hatching in
A calculation result when the above-described correction processing according to the first embodiment is executed will be compared with that of the conventional method by referring again to
error when no processing is performed: ((a)−(b))/(b)=0.216
error when processing according to the conventional method is performed: ((c)−(b))/(b)=0.103
error when processing according to the first embodiment is performed: ((d)−(b))/(b)=0.196
These results reveal that an error remaining after the processing according to the first embodiment is larger than an error remaining after the processing according to the conventional method, but the error is reduced in comparison with the case in which no correction processing is performed. Note that the example of
Correction processing according to the second embodiment will be explained with reference to
In the second embodiment, in step S7 in the flowchart shown in
Correction processing according to the third embodiment that improves the processing efficiency by excluding division processing for a partial pattern having a substantially less action will be described with reference to
In contrast, pattern data obtained after performing division processing for only the first portion formed from the large figure without performing division processing for the second portion formed from the small figure is indicated by hatching surrounded by solid lines in
The residual errors, from accurate correction results indicated by chain lines in
Aspects of the present invention can also be realized by a computer of a system or apparatus (or devices such as a CPU or MPU) that reads out and executes a program recorded on a memory device to perform the functions of the above-described embodiment(s), and by a method, the steps of which are performed by a computer of a system or apparatus by, for example, reading out and executing a program recorded on a memory device to perform the functions of the above-described embodiment(s). For this purpose, the program is provided to the computer for example via a network or from a recording medium of various types serving as the memory device (for example, computer-readable medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’). In such a case, the system or apparatus, and the recording medium where the program is stored, are included as being within the scope of the present invention.
The present invention is applicable as a method of creating, from design pattern data of a semiconductor integrated circuit such as an LSI, drawing data which can be input in a charged particle beam drawing apparatus. The present invention is also available in a lithography apparatus such as an ultrashort ultraviolet exposure apparatus, X-ray exposure apparatus, or multi-electron beam drawing apparatus.
[Article Manufacturing Method]
An article manufacturing method according to an embodiment of the present invention is suitable for manufacturing a microdevice such as a semiconductor device, and an article such as an element having a microstructure. This manufacturing method can include a step of forming a latent image pattern on a photosensitive agent applied to a substrate by using the aforementioned lithography apparatus (step of forming a pattern on a substrate), and a step of developing the substrate on which the latent image pattern is formed in the preceding step. Further, the manufacturing method can include other well-known steps (for example, oxidization, deposition, vapor deposition, doping, planarization, etching, resist removal, dicing, bonding, and packaging). The article manufacturing method according to the embodiment is superior to a conventional method in at least one of the performance, quality, productivity, and production cost of an article.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2013-009616, filed Jan. 22, 2013, which is hereby incorporated by reference herein in its entirety.
Claims
1. A generation method of generating drawing data for performing drawing on a substrate by a drawing apparatus based on pattern data associated with a two-dimensional grid, the method comprising steps of:
- dividing the two-dimensional grid into a plurality of rectangular regions based on an angle by which the pattern data is rotated; and
- obtaining a translation amount of partial data of the pattern data with respect to each of the plurality of rectangular regions based on the angle.
2. The method according to claim 1, wherein the dividing step performs the dividing based on the angle and a unit size of the two-dimensional grid.
3. The method according to claim 1, wherein letting L be a size of each of the plurality of rectangular regions, TH be the angle, and Dx and Dy be representative coordinates of the partial data normalized by L, each of SRx and SRy be the translation amount, the obtaining step obtains the translation amount based on equations:
- SRx=−L×TH×Dy, and
- SRy=L×TH×Dx.
4. The method according to claim 1, wherein two adjacent sides of each of the plurality of rectangular regions have respective lengths different from each other.
5. The method according to claim 4, wherein a size of each of the plurality of rectangular regions is determined based on a size of a pattern represented by the pattern data.
6. The method according to claim 1, wherein if a pattern represented by the pattern data is smaller than a size of one of the plurality of rectangular regions and extends into at least two of the plurality of rectangular regions, the translation amount is not obtained for the partial data corresponding to the pattern.
7. A processing apparatus for processing pattern data associated with a two-dimensional grid to generate drawing data for performing drawing on a substrate, the apparatus is configured to execute:
- first processing of dividing the two-dimensional grid into a plurality of rectangular regions based on an angle by which the pattern data is rotated; and
- second processing of obtaining a translation amount of partial data of the pattern data with respect to each of the plurality of rectangular regions based on the angle.
8. A storage medium storing a program for causing a computer to execute a generation method of generating drawing data for performing drawing on a substrate by a drawing apparatus based on pattern data associated with a two-dimensional grid, the method comprising steps of:
- dividing the two-dimensional grid into a plurality of rectangular regions based on an angle by which the pattern data is rotated; and
- obtaining a translation amount of partial data of the pattern data with respect to each of the plurality of rectangular regions based on the angle.
9. A drawing apparatus for performing drawing on a substrate with a charged particle beam based on drawing data, the apparatus comprising a processing apparatus for processing pattern data associated with a two-dimensional grid to generate the drawing data; wherein the processing apparatus is configured to execute:
- first processing of dividing the two-dimensional grid into a plurality of rectangular regions based on an angle by which the pattern data is rotated; and
- second processing of obtaining a translation amount of partial data of the pattern data with respect to each of the plurality of rectangular regions based on the angle.
10. A method of manufacturing an article, the method comprising steps of:
- performing drawing on a substrate using a drawing apparatus;
- developing the substrate having undergone the drawing; and
- processing the developed substrate to manufacture the article,
- the drawing apparatus performing drawing on the substrate with a charged particle beam based on drawing data, the apparatus including:
- a processing apparatus configured to process pattern data associated with a two-dimensional grid to generate the drawing data,
- wherein the processing apparatus is configured to execute:
- first processing of dividing the two-dimensional grid into a plurality of rectangular regions based on an angle by which the pattern data is rotated; and
- second processing of obtaining a translation amount of partial data of the pattern data with respect to each of the plurality of rectangular regions based on the angle.
Type: Application
Filed: Jan 22, 2014
Publication Date: Jul 24, 2014
Applicant: CANON KABUSHIKI KAISHA (Tokyo)
Inventor: Yusuke Sugiyama (Utsunomiya-shi)
Application Number: 14/160,688